Vacuum moistening process



Dec. 13, 1938. M. A. HlRscHL ET AL 139,681

VACUUM MOISTENING PROCESS Filed Oct. ll, 1937 Patented Dec. 13, E93@ unirn starte aiiatti editeur ortica'.

Appiicaton ctober l1, 1937, Serial No. 168,529

2 Glaims.

This invention relates to a process for moistening products, primarily organic, in which a vacuum is employed followed by steaming.

In such an operation the organic product is 5 subjected in bulk to a vacuum in a closed chamber, and after removal of most of the non-condensible gas, steam is admitted while retaining a vacuum in the tank, and after the moistening operation is completed, the tank is open to the air which is allowedl to enter the tank and raise the pressure to atmospheric.

It has now been discovered that in such a treatment there is a tendency to dry out such portions of the organic product as may be somewhat more exposed. For instance, in ahogshead of tobacco, those portions ofthe tobacco which are` exposed between the boards are found to be somewhat more dry than the central leaves.

It has now been discovered that a considerable portion of this dryness is due to the admission of air as the nal stage in the operation of the process. The air that enters the tank at this stage, even if originally saturated .with Water vapor, while expanding has a great capacity for water and therefore has a very serious drying eect. upon material over which itv passes.

-In accordance'with the present invention, the air admitted to the tank is supersaturated with water either in the form` of steam or as finely divided liquid water so that the products which it meets rst in its travel will not be subjected to a drying operation.

Furthermore, as the pressure continues to rise in the tank, the 'capacity of the air therein for water becomes less, so that ultimately that moisture added to the air above saturation is precipitated out upon the product being treated.

The invention is illustrated diagrammatically' =in the drawing in which i is a tight tank of any desired design equipped with a door ll a vacuum outlet i3 leading to any suitable vacuum pump or jet, preferably one capable of `producing a vacuum sufcient to cause Water contained in the organic productto boil.

The tank is also provided with a steam inlet i6 and an air inlet or vent i2. Associated with, and preferably directly within, the air inlet l2 is a line l controlled by valve i8 through which steam 50 .or Water may be introduced.

Likewise, within the .tank is a spray it. through (Cil. 1311-55) After the moistening operation is complete, the

valve l'i on the air inlet |12 is opened and air allowed -to enter the tank, at the same time the steam line ldbeing opened and steam admitted through the valve i8. The ratio of steam to air is, adjusted in accordance with the temperature of the tank, the temperature of the air and the moisture content of the air, so that the air will not be unduly heated, and at the same time sov that it will not have an appreciable drying effect. It is preferred to supersaturate the air very substantially with moisture.

In certaincases it may be desirable to introduce liquid water through the line I8, but in this event it is preferred to use a fog nozzle of any Aordinary type in order to atomize the Water. In this manner, if the moisture is made ne. enough the incoming air. will carry some of the liquid water into the tobacco and further moisten it.

The invention is applicable to other products such as grain, or even to inorganic products; air and moisture are factors.

We claim:

1. The method oftreating a productto moisten it, which comprises subjecting the product to a high vacuum, admitting steam thereto while maintaining a high vacuum, and then breaking the vacuum by admission ,of air supersaturated With moisture. L Y

2. The method of treating a'product to'moisten it, which comprises subjecting the product to a higlr vacuum, adnfiitting steam` thereto While maintaining a vacuum, and then breaking the vacuum by admitting air thereto and simultaneously introducing moisture with the air, whereby evaporation of moisture by the air is'substan- 'tially avoided.

MARCUS A. mSCBL. CHARLES J. MERRIAM. 

